0

0.4

0.8

1.2

1.6

2

2.4

2.8

3.2

3.6

4

-110

-100

-90

-80

-70

-60

-50

-40

-30

-20

-10

0

10

D002

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5

-0.5

-0.5

-0.4

-0.4

-0.3

-0.3

-0.2

-0.2

-0.1

-0.1

0

0

0.1

0.1

0.2

0.2

0.3

0.3

0.4

0.4

0.5

0.5

D002

Pass-Band Ripple

Phase Deviation

22

PCM1840

SBAS989 – APRIL 2019

www.ti.com

Product Folder Links: PCM1840

Submit Documentation Feedback

Copyright © 2019, Texas Instruments Incorporated

7.3.7.2.2

Low-Latency Filters

For applications where low latency with minimal phase deviation (within the audio band) is critical, the low-

latency decimation filters on the PCM1840 can be used. The device supports these filters with a group delay of

section provides the filter performance specifications and various plots for all supported output sampling rates for

the low-latency filters.

7.3.7.2.2.1

Sampling Rate: 16 kHz or 14.7 kHz

Figure 38 shows the magnitude response and Figure 39 shows the pass-band ripple and phase deviation for a

decimation filter with a sampling rate of 16 kHz or 14.7 kHz. Table 15 lists the specifications for a decimation

filter with a 16-kHz or 14.7-kHz sampling rate.

Figure 38. Low-Latency Decimation Filter Magnitude

Response

Figure 39. Low-Latency Decimation Filter Pass-Band

Ripple and Phase Deviation

Table 15. Low-Latency Decimation Filter Specifications

PARAMETER

TEST CONDITIONS

MIN

TYP

MAX

UNIT

Pass-band ripple

–0.05

0.05

dB

Stop-band attenuation

87.3

dB

Group delay or latency

7.6

Group delay deviation

–0.022

0.022

Phase deviation

–0.21

0.25

Degrees